The present disclosure relates to image forming apparatuses and particularly relates to a technique for sorting sheets contained in a sheet feed cassette according to a predetermined condition.
There have recently been image forming apparatuses having a function of a sheet sorting device for sorting sheets on which images have been formed (printed). Examples of such a technique for sorting sheets include the following first to third techniques. The first technique is a technique through which the operating time for sorting sheets after a copy work can be reduced. The second technique is a technique in which: any spot on a sheet is detected for each side of the sheet by a sensor; when any spot is detected only on one side of the sheet, printing is performed only on the other side of the sheet where no spot has been detected; when no spot is detected on both sides of the sheet, the sheet is sorted to a reverse side tray; and when any spot is detected on both sides of the sheet, the sheet is sorted to a reject tray. The third technique is a technique in which the size of a blank space of a printed sheet is detected by a blank space detector and the sheet is sorted according to the detected size.